Nissan Repair: 00 Frontier Valve Tapping?, cam follower, nissan service

Question
I bought my Frontier (2000 V6 2WD VG33 Engine)used @18 months ago w/72k.  About a week after purchase heard a tapping in engine.  Dealer's mechanic stated he changed plugs...until he found "too thin a motor oil was used."  Tapping was gone.  Tapping has returned (92K miles) This occurs on start sometimes and others after warm up.  The noise sounds like a lifter but it is inconsistant sometimes and regular other times.  I had one independant mechanic tell me he suspected debris in the head  ($800 labor alone), Nissan service manager and mechanic said it was a lifter and I should go to Autozone for engine treatment and don't worry about it b/c it won't hurt anything. What do you think?

Answer
Dave,

If the lifter or cam follower, as it is, is ticking then I would change to the 5W30 engine oil and keep it changed.  If the tick is inconsistant there should be no reason to change it.  If it is loud and constant I would change it.  But, from what you say it should be fine.